Sōshi-kaimei (創氏改名) was a policy created by Jiro Minami, Governor-General of Korea under the Empire of Japan, implemented upon Japanese subjects from Korea (referred to below as Koreans). As defined by Ordinance No. 19, issued in 1939, sōshi, literally "creation of a family name" (氏, shi^?), was mandatory because, under the Japanese interpretation, Korean family names were not family names but clan names (姓, sei^?) which indicate a person's father's origin, while by Ordinance No. 20, issued in 1940, kaimei, literally "changing (your) given name", was voluntary and would be charged a fee. This was effectively a reversal of an earlier government order forbidding Koreans from taking Japanese names. There are various explanations of the purpose of the ordinances.

In 1909, the Korean Empire established a civil registration law (民籍法, minsekihō^?), starting the creation of a modern family registry system. With regards to the recording of details about women such as the father's surname, age, and connection to the registry holder, due to attention that needed to be given to avoiding conflict with Korean customs, the drafting of the law was not completed until April 1910, just before the annexation of Korea. By that time, a portion of Koreans had already registered Japanese-style names and the like, which generated confusion. As a result, on the basis of memoranda such as Order No. 124, "Document regarding name changes by Koreans" issued by the Governor-General of Korea on November 11, 1911, the use by Koreans of "names which might be mistaken for those of native Japanese" was no longer permitted, and strict controls were placed on the registration of Japanese-style names for newborn children. Additionally, Koreans who had registered Japanese-style names on there were required to revert to their original names.